Various different forms of hot box detecting systems have been heretofore designed. Examples of these previously known detecting systems are disclosed in U.S. Pat. Nos. 2,521,469, 2,897,775, 3,440,416, 3,546,448 and 3,790,777. Further, an alarm signal for heated bearings is disclosed in U.S. Pat. No. 859,925.
However, these previously known systems and devices are not fully capable of automatically bringing a train experiencing a hot box condition to a halt as a result of repeated monitoring of all of the bearing journals of the train and also capable of rendering both visual and audible signals in the caboose and engine of a train experiencing a hot box condition prior to automatic stopping of the train. Further, these previously known devices do not also include readily installable substantially fail-safe wheel axle mounted signal generators which are retained in inoperative fully enclosed condition until such time as they are actuated by a hot box condition.